Electrical induction apparatus



,Oct.-27, R. J. .BORRUP n I 3, ,049

ELECTRICAL INDUCTION APPARATUS Filed April 15, 1969 INVENTOR.

RONALD J. BORRUP ATTORNEYS United States Patent 3,537,049 ELECTRICAL INDUCTION APPARATUS Ronald .I. Borrup, RoBoR Company, 1305 Main St., Glastonbury, Conn. 06033 Filed Apr. 15, 1969, Ser. No. 816,207 Int. Cl. H01f 27/08 US. Cl. 336-61 7 Claims ABSTRACT OF THE DISCLOSURE The apparatus of this invention includes a significantly improved latent vaporization cooling and winding system for a transformer having a series of tubular sections providing a single continuous transformer winding with the tubular sections each having closed ends and defining zit) plurality of discontinuous sealed liquid coolant chamers.

This invention generally relates to transformer cool- 1ng systems and particularly those types of systems using latent heat vaporization of a coolant to provide more effective heat transfer.

A primary object of this invention is to provide a transformer cooling system exhibiting improved heat dissipation while providing substantial reductions in size and cost of the apparatus.

Another object of this invention is to provide an improved combination cooling and winding system for a transformer particularly suited for different end use applications wherein system losses generated from the heat of transformer operation can be used to provide desired ambient heating.

A further object of this invention is to provide an improved transformer cooling and winding system which is economical to manufacture and assemble and which will provide reliable operation over an extended period of time while being virtually free of service requirements.

Other objects will be in part obvious and in part pointed out more in detail hereinafter.

A better understanding of the invention will be obtained from the following detailed description and the accompanying drawing of an illustrative application of the invention.

In the drawing:

FIG. 1 is an isometric view showing a portion of a transformer embodying this invention with the insulation material and primary windings removed for purposes of clarity;

FIG. 2 is an enlarged view, partly in section, of the transformer of FIG. 1 shown with insulation material and primary windings; and

FIG. 3 is a reduced end view of the transformer, partly in section and partly broken away.

Referring in detail to the drawing, a transformer constructed in accordance with this invention is shown having a conventionally laminated elongated core 12 and first and second windings. For illustrative purposes, it may be assumed that windings 14 are high voltage windings carrying approximately amps and the transformer 10 is being used to step-down voltage from, say, 220 volts to about volts, for an end use application having amperage requirements in the neighborhood of 150 amps. Accordingly, it will be seen that very substantial heat dissipation problems will be encountered in the operation of such a transformer, and the conventional transformer normally used to meet such requirements is typically of massive size and volume to afford very large surface areas to provide the necessary coiling.

To overcome any possible overheating of the transformer components and to control objectionable concentration of heat while at the same time providing an 3,537,049 Patented Oct. 27, 1970 available source of thermal energy for any desired ambient heating in a transformer of reduced size and cost, a combination latent vaporization cooling and winding system is provided for in accordance with this invention to form a single continuous winding, while also providing a substantially improved cooling system for the transformer 10.

More specifically, a conductor 16 is formed of a series of discrete hollow tubular sections or tubes such as at 18 and 20, each of which are generally shaped in the form of a loop with end portions 18', 20' shown extending upwardly away from the loop above the uppermost level of the transformer core 12 to provide a plurality of good thermal conducting paths to the atmosphere. The end portions 18', 20' of each tube 18, 20 are shown spaced apart longitudinally of the core 12 in contact with the end portions of an adjacent tube and preferably fixed or soldered such as at 22. Thus a single continuous Winding is ensured with each tube 18, 20 constituting an individual turn and providing an excellent thermal conducting path by virtue of its extended end portions. Of course, other conditions can be used such as, e.g., a solid rod winding with each of its turns having end portions extended away from the transformer core.

It will be understood that any necessary electrical insulation as at 24 between the conductor 16 (which for illustrative purposes only will be considered as the low voltage winding), the core 12 and the high voltage windings 14 may be provided by any suitable commercial material, such as silicon rubber or similar conventional insulation materials.

To ensure that the conductor 16 will provide not only a satisfactory current path for the transformer 10, but to additionally ensure a significantly improved transformer cooling action and more effective heat dissipation permitting desired reduction in transformer size and cost, the individual tubes 18, 20 are partially filled with a suitable coolant 26 such as commercially available refrigerant fluids, water, or a water mixture including a suitable freeze point depressant, and the ends of each tube 18, 20 are closed such as at 28, thereby providing a series of sealed liquid coolant chambers 30 wherein the coolant 26 is trapped within each chamber extending in distributed relation about the core 12. In addition, it may be desirable to add a corrosion inhibitor or similar additives to the coolant 26 to provide desired functions in specific transformer applications.

By virtue of the above construction, latent vaporization characteristics of the liquid coolant 26 can be effectively and efficiently used to dissipate heat generated during normal operation of the transformer 10, for no temperature difference will exist within the sealed coolant chamhers 30 and an exceptionally efiicient path is provided by the above-described structure for transmitting thermal energy from the winding assembly to the atmosphere. Thus, during operation of the transformer 10 the liquid coolant 26 is caused to boil and vaporize, thereby effectively withdrawing heat from the winding assembly of the transformer 10. The vapor rises into the closed end portions of its tube 18 whereupon its heat is released due to the temperature gradient between the coolant mixture and the relatively isolated closed tube end portions. Thereupon the vapor condenses and reforms as a liquid within the closed system in each tube 18, 20.

Such heat exchange is preferably improved by the provision of exterior cooling fins 32 shown secured to the end portions 18', 20 of each tube 18, 20, and even more efficient transmission of the dissipated heat into the ambient air may be elfected if desired with the assistance of a suitable fan or blower arrangement, not shown.

A transformer constructed in accordance with this invention will incorporate an exceptionally effective cool ing system for practical use in a number of different end use applications wherein the ambient air is desired to be heated, with minimal total system energy loss. In addition, regardless of the attitude of the transformer core 12, the individually sealed coolant chambers 30 within each tube 18, 20 Will provide for efficient heat dissipation of the core 12 surrounded by the conductor 16. Any danger of overheating a transformer component intended to be cooled, due to a change in the attitude of the transformer 10, is elfectively minimized since coolant 26 is trapped within each of the several individually sealed chambers 30. In the event of a leak in a section of the conductor 16, no danger exists of losing the entire coolant charge, and the system may well continue to be relatively effective even if a few of the tubes 18 were to become corroded or otherwise damaged. A transformer properly designed in accordance with this invention will provide increased surface areas available for heat dissipation, whereby a transformer can be provided of significantly reduced size and cost while at the same time ensuring relatively trouble-free dependable service over an extended service life.

As will be apparent to persons skilled in the art, various modifications, adaptations and variations of the foregoing specific disclosure can be made without departing from the teachings of the present invention.

I claim:

1. Electrical induction apparatus comprising core means, and winding means for the core means including a plurality of turns collectively forming a single continuous electrical conductor surrounding the core means with each turn being formed by a hollow tubular section having closed ends and defining an individually confined, isolated fluid coolant chamber.

2. The apparatus of claim 1 wherein the tubular section for each turn is generally formed in the shape of a loop with said closed ends extending away from the loop.

3. The apparatus of claim 1 further including a liquid coolant trapped within each tubular section of the winding means and partially filling the chamber within each turn for circulation therein in vapor cooling heat transfer relation to the core means.

4. The apparatus of claim 2 wherein one of said closed ends extends upwardly away from the loop and is disposed above the core means.

5. The apparatus of claim 4 wherein an exterior cooling fin is connected to said one closed end.

6. A closed latent vaporization cooling and electrical winding system for a transformer comprising a core, and a. series of generally loop shaped tubular sections each forming a turn surrounding the core, the tubular sections each having closed end portions extending upwardly away from the loop above the core and forming a confined liquid coolant chamber, liquid coolant trapped in each chamber and partially filling the same, adjacent tubular sections being connected in electrical contact and collectively forming a single continuous winding for the core, and an exterior cooling fin secured to said closed end portions of the tubular sections.

7. The winding system of claim 6 wherein the closed end portions of adjacent tubular sections are interconnected to form a single continuous winding for the core.

References Cited UNITED STATES PATENTS 1,547,497 7/1925 Hunter 336-223 XR 1,995,301 3/1935 Gebhard 336-62 2,355,560 8/1944 Roberds 336-62 2,907,968 10/1959 Thiink 336-223 XR 3,024,431 3/1962 Ginton 336-62 r THOMAS J. KOZMA, Primary Examiner US. Cl. X.R. 

